1. Field of Invention
This invention relates generally to masonry structures, and more particularly, to reinforcement and retrofitting of masonry or foam core structures exposed to extreme wind and/or seismic loading events.
2. Description of Related Art
Masonry structures are common in residential and light commercial construction. In the case of masonry construction, the structure should be protected from uplift, shear, and overturning forces developed by wind or seismic activity. In the United States, the amount of wind and seismic activity differs with geographical location, which is shown by differences in local building codes throughout the country. In many structures, reinforcing concrete masonry unit (CMU) walls resists these forces. In new construction, this is accomplished by filling vertical cells of the masonry wall with concrete and steel reinforcing bars at a given spacing. The number of reinforced cells and the strength of concrete and steel used will vary depending on the severity of the wind and/or seismic conditions in the locality of the structure, and the structure's geometry.
In many instances, the steel reinforcing is installed during the foundation and masonry installation. Steel anchor bars are installed into the foundation footings as required by the loads and extends upward beyond the footings approximately two to three feet. The CMUs are then installed over the steel bars so that the steel bars are in the center of the cell (or void within the masonry unit). After the CMU wall is constructed, additional steel that extends from the foundation to the top of the wall is installed. Next, concrete is poured into the cell around the steel bars.
Flexible steel tie members can be used instead of steel bars. These steel tie members span from the foundation to the top of the CMU wall, and they typically take the form of steel strands or steel cable. It can be difficult to insert the flexible tie members after wall construction since the natural coil in the tie member is not conducive to threading through narrow vertical voids in the wall. The free end of flexible tie members tends to become snagged or entangled during the installation process, making use of flexible steel tie members difficult or impossible.
Therefore, what is needed is a guide member installed within vertical passageways in the wall to assist in installing the flexible tie members inside the wall.